A computer system has been known where edge servers are placed at respective locations, and a core server that can communicate with each edge server is placed at a data center apart from the locations (e.g., PTL 1). At each location, the edge node provides a client with a namespace (hereinafter a local namespace), such as a file system, and the client updates the local namespace (e.g., a change operation (e.g., creation, update, deletion, renaming, or copy) is applied to the objects (directories and files) in the local namespace). Update of the local namespace provided by any of the edge nodes is applied to the namespace (hereinafter a center namespace) managed by the core node (migration). The update of the center namespace managed by the core node is applied to the local namespace provided by another edge node (synchronization). The edge nodes thus share the namespace.
Different change operations to an identical object in different local namespaces can cause confliction of objects. PTL 1 resolves confliction by moving the conflict file to a special directory for evacuation. NPL 1 resolves confliction by any of a method of moving the conflict file to a special directory for evacuation and a method of overwriting, on the conflict file, a file subjected to another change operation.